
The `network` option expects a string stating the network setting for building the image.

#### Example: Defining a Network for Docker
```yaml
images:
  backend:
    image: john/appbackend
    build:
      docker:
        options:
          network: host
```
**Explanation:**  
The image `backend` would be built using `docker` and `docker build` would be called using the `--network=host` flag.
